This invention relates to a photometer for use with a microscope.
The Leitz MPV 3 is a microscope photometer having a divider surface which splits up a light beam between a microphotometer and a microscope eyepiece. In the imaging optical path to the microphotometer a pin hole occluder cuts a region of the field to be measured in the image of the object. The pin hole occluder is illuminated from behind so that a beam passes through the pin hole occluder through the divider surface to a mirror which images the pin hole occluder in an intermediate image in the microscope eyepiece. In this way the pin hole occluder is imaged in the intermediate image together with the direct image of the object.
In the Leitz MPV 3 microscope photometer the mirror is a triple mirror, and is arranged to reflect each light beam back on itself. The pin hole occluder is imaged in the microscope eyepiece as the brightest spot, which is superimposed on the direct image of the object in the microscope eyepiece. However one disadvantage of known microscope photometers is that they do not permit the superimposition of a further image into the microscope eyepiece additional to the image of the pin hole occluder.